Abstract: Summary The taxonomic status of all equid species is not completely unravelled. This is of practical relevance for conservation initiatives of endangered, fragmented equid populations, such as the Asiatic wild asses (in particular Equus hemionus onager and E. hemionus kulan). In this study, a marker panel consisting of 31 microsatellite loci was used to assess species demarcation and phylogeny, as well as allocation of individuals (n = 120) to specific populations of origin (n = 11). Phylogenetic analysis revealed coalescence times comparable with those previously published from fossil records and mtDNA data. Using Bayesian approaches, it was possible to distinguish between the studied equids, although individual assignment levels varied. The observed results support the maintenance of separate captive conservation herds for E. hemionus onager and E. hemionus kulan. The first molecular genetic results for E. hemionus luteus remained contradictory, as they unexpectedly indicated a closer genetic relationship between E. hemionus luteus and E. kiang holderi compared with the other hemiones.

Abstract: UNGULATE communities of two East African savannas, the Serengeti and Athi-Kapiti Plains, are dominated by wildebeest (Connochaetes taurinus) supplemented by zebra (Equus burchelli), topi (Damaliscus lunatus), hartebeest (Alcelaphus buselaphus), buffalo (Syncerus caffer) eland (Taurotragus oryx) and gazelles (Gazella grand and G. thomsoni)1-3. Before this research, little was known of East African large mammal communities in the Late Pleistocene and early to middle Holocene. We document an extinct impala-sized alcelaphine antelope that is numerically dominant in Late Pleistocene archaeofaunal assemblages from the Athi-Kapiti Plains. The extinct giant buffalo Pelorovis antiquus is present, and a number of arid-adapted regionally extinct species are common. The small alcelaphine is rare in northern Tanzania, but regionally extinct arid-adapted species are present in Late Pleistocene deposits. These data indicate that as recently as 12,000 years ago, the large mammal community structure of East African savannas was very different and dry grasslands and arid-adapted ungulates expanded at least as far south as northern Tanzania during the Last Glacial Maximum.

Abstract: Feral horses are social animals, which have to rely on survival strategies centered on the formation of cohesive social bonds within their bands. Many problems in the husbandry of social animals such as horses, are due to the fact that the limits of their adaptive abilities are exceeded. Evidence suggests that the fundamental social characteristics of domestic horses have remained relatively unchanged. The social structure, social strategies and social interactions were investigated (3 non-consecutive years, 24 hr per day for several weeks) in long term established groups of domestic horses (mares and geldings of all ages) and a few small introduced groups, kept in (semi)natural environments. The general aim was to investigate the social needs of domestic horses. The social life of domestic horses was characterised by long lasting bonds with preferred partners which were established and maintained by allogrooming, play, proximity and dominance behaviours. Bonding partners were mainly found within the same sex-age group, but adult geldings also bonded with sub-adult mares and geldings. Adult mares were clustered in a group, while the other animals formed a second group. Among the adult mares, subgroups according to reproductive state were formed. Individuals regulated their social network by interfering with interactions between other members of the herd, which in itself is complex. An intervention is a behavioural action of one animal that actively interferes with an ongoing interaction between a dyad with the apparent aim of altering that interaction. This was verified by post-hoc analyses of disturbed and undisturbed interactions. Interventions in allogrooming or play were performed significantly more often when at least one member of the initial dyad was a preferred partner of, or familiar to (within the small introduced bands) the intervener. The stronger the preferred association in allogrooming between the intervener and member(s) of the initial dyad, the higher the probability the intervener would displace one initial member and continue allogrooming with the other. Just five behaviours were extracted which reliably reflected the dominance relations among horses. Aggression with the hind quarters was used both offensively and defensively and therefore not suitable as a reliable parameter. Individual dominance relationships were related to social experience. The implications of these findings for horse husbandry were assessed. It is argued that the execution of affiliative behaviours may be rewarding in itself, and therefore always will be a highly motivated behaviour. It is shown that social positive physical interactions (allogrooming, play) with other horses is an ethological need and therefore indispensable in modern husbandry systems. Ethological needs are so important for the animal that husbandry systems that lack the possibilities to execute such behaviours will cause chronic stress. It is concluded that all horses need physical social contact, and that horses, which lack appropriate social learning experiences during ontogeny, may be hampered in their social functioning later in life. Solutions for problems, including dominance problems, in individual social housing and group housing are presented.

Abstract: Variations in birth sex ratios and sex differences in juvenile mortality occur in a number of mammalian species, and in many cases have been linked to resource availability. Most of these biases in offspring sex ratios concern polygynous species with pronounced sexual dimorphism, and where females only are philopatric. Data on species with unusual life-history strategies, such as slight sexual dimorphism or dispersal by both sexes, are of particular interest. In this study of a natural herd of horses (Equus caballus) which experienced an eruptive cycle, and therefore a period of nutritional stress, male offspring had higher neonatal mortality rates in nutritionally poor years than in good ones, whereas “year quality” had no effect on the mortality of female offspring; year quality could therefore be used by mares as predictor of sex-specific offspring survival. We show that the environmental conditions that predicted lower survival of males were negatively related to their production: the birth sex ratio the following year was female-biased; and mares were less likely to produce a son when they had produced a son the preceding year. There was no significant effect of mother's parity, age or rank, or the timing of conception or birth on offspring sex ratios. The mechanism leading to biases in the birth sex ratio could have been the loss of male embryos by mares that did not foal. As there was no evidence for selective abortion of male foetuses in females that did foal the next year, it is not necessary to invoke maternal adjustment, though this remains a possibility. Finally, there was a suggestion that male offspring were more costly to raise than females, since mothers that reared a son in poor years tended to experience an increase in the interbirth interval between their two subsequent offspring.